Gas diffusion means for liquid storage tanks



Jul y 10, 1945. s. T. HELSETH ET AL GAS DIFFUSION MEANS FOR LIQUID STORAGE TANKS Filed Jan. 20, 1942 3nventor S/GURD 7.' HELSETH 8 STANLEY 7'.FAUVER (Ittorneg Patented July 10, 1945 GAS DIFFUSION MEANS FOR LIQUID STORAGE TANKS Sigurd T. Helseth and Stanley T. Fauver, Paines ville, Ohio, assignors to Industrial Rayon Cor- I .poration, Cleveland, Ohio, a corporation of Delaware A Application January 20, 1942, Serial No. 427,528

4 Claims.

This inventionrelates. to gas diffusion means for liquid storage tanks.

In many industries, it is the practice to use gas pressure to discharge liquids, pastes, semi solids, etc. from storage tanks. While in some cases the manner in which the 'gas is introduced into the tank is of no apparent consequence, in others it constitutes a serious problem. An example of the latter is to be found in the rayon industry, wherein air under pressure is customarily introduced at or near the top of the spin tank in order to maintain an uninterrupted flow of spinning solution to the thread-forming machines. The problem is especially troublesome in installations in which the viscose process is employed.

Under such circumstances, if air is introduced into the spin tank by means of an ordinary openend pipe, the onrushing air splashes viscose from the surface of the mass, depositing it upon the walls and ceiling ofthe tank. Since viscose sets, or solidifies, on standing, continued splashing tends to build up icicle-like solids which, when they eventually break off, clog the outlet screen at the bottom of the tank. Furthermore, the skin which normallyforms on the walls-and ceiling of the tank tends to rupture under the action of the air current, falling to the tank :bottom in one or more large pieces.

By providing means within the tank for preliminarily diiiusing theair employed to discharge the viscose, ,the present invention obviates these difiiculties. l

The invention also minimizes troubles which arise when, as occasionally happens, the spin tank is accidentally overcharged with viscose, which in such case backs up into the air pipe. Not only does the entrance of viscose into the air supply line cause immediate difficulties, but the viscose clings to the interior and exterior of the pipe, causing complications when coagulation occurs. Even if the viscose does not entirely obstruct the interior of the air supply pipe, adherent masses form inside the pipe which, by reducing its. cross-sectional area, increase the velocity of the gas stream, thus greatly aggravating the difiiculties hereinabove described.

Because the invention has particular applicaof a preferred embodiment of the invention with a portion of the diffusing device broken away. Figure 3 is a transverse cross-section of the device of Figure 2. Figure 4 shows a plan of another embodiment of the invention with a portion of the diffusing device similarly broken away. Figure 5 shows the same embodiment in cross section. Figure 1 illustrates a storage tank 5 of the kind referred to in the rayon industry as a spin tank. The tank is for the most part of conventional construction, being mounted in the usual way upon a standard 6. It is equipped with an inlet connection 1 for fresh viscose and an outlet connection 8 for viscose supplied to the spin machines. Toward the top thereof, provision is made for a suction line 9a and a gas supply pipe 9b through the latter of which is supplied air or other inert gas capable-of being employed to force the viscose out of the tank into the spin machine supply lines.

In accordance with the teachings of the invention, a diffusing device it is mounted by means of a coupling l l on gas supply pipe 9b. Together with gas supply pipe 91), the diffusing device I0 is located in the space immediately above the level 62 reached by the viscose l3 when tank is filled to its normal capacity; so that under ordinary conditions diffusing device II] is at all times well above the level of the liquid. When gas under pressure reaches diffusing device ID from gas supply pipe llb the gas is diffused as hereinafter explained with a, minimum of turbulence at or beneath the liquid surface.

In Figure 2, which shows'the gas diffusing device It] in detail, extension I l comprising a pipe or conduit similar to gas supply pipe 9b but provided with apertures I5 in its upper semi-circular segment passes diametrically through the top portion of an inverted concave deflector I! of generally cylindrical shape. Pipe cap I6 blocks 01f what would otherwise be the open end of pipe extension 14. A shallow conical or convex member i8 is mounted on hangers [9 inside deflector I1: its apex is disposed in such relation to the top of the deflector as to allow ample room for gas to pass therebetween.

In operation, gas under pressure is emitted from apertures 15 in pipe extension l4. As already indicated, such apertures are so located as to direct the gas against the top of deflector ll The latter deflects the gas against conical member l8, which in turn diffuses the gas over a relatively broad area before permitting it to escape around the circular base of the conical member. In this way,

a spreading of the gas is obtained, thus obviating splashing of the viscose.

By virtue of the shape of deflector II, it is impossible for viscose to enter the gas supply line 91). Being imperforate except for the broad opening at the bottom thereof, deflector I1 is capable of acting to trap air in much the same manner as a diving bell. Because the air supply is shut off when the tank 5 is being filled, pipe extension l4 and gas supply pipe 91) offer no means of escape for the entrapped gas. Thus if tank 5 is charged by accident with quantities of viscose beyond its normal capacity, the viscose is prevented by air trapped within deflector I! from entering pipe extension l4.

Figures 4 and 5 shows an embodiment of the gas diffusin device differing only slightly from that shown in Figures 2 and 3. In the construction illustrated in Figures 4 and 5, diffusion means are employed taking the form of a per forated plate 2| mounted on a generally concave deflector 22. Although both embodiments serve the same purposes, in the device shown in Figures 4 and 5 the perforations in plate 2! allow gas to escape simultaneously at many points. In the device of Figures 2 and 3 on the other hand, the gas escapes only around the periphery of conical member l8.

The effectiveness of the gas diffusing device of the invention is such that the splashing of the viscose at the surface formerly caused by the sudden introduction of gas into the tank has been virtually completely eliminated. By elimi nating splashing, this device has served to avoid the formation of solids which ordinarly would clog the outlet of the tank; at the same time, by preventing viscose from backing up the gas supply line, the need for repeatedly cleaning the gas supply line has been minimized. In practice, the device greatly facilitates operations.

Obviously, gas diffusing devices constructed according to the principles of the invention may be expected to have application not only in the handling of viscose, but in the handling of syrups, molasses and other materials which tend to sugar out or solidify. Similarly, the invention may be employed in diffusing gases which are to be introduced into tanks containing chemicals, particularly in cases in which it is necessar to avoid sudden turbulence within the bulk of the material. Other applications of the invention will readily suggest themselves.

Various modifications of the gas diffusing devices illustrated in the drawing may be made in shape, disposition, method of mounting, etc., without departing from the spirit of the invention. The number and. placement of the perforations in plate M can of course be widely varied. In either case, the device as a whole can readily be supported from the top of a storage tank. Other modifications will be readily apparent to those skilled in the art to which the invention appertains.

It is intended that the patent hall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside inth invention. 1

What is claimed is:

1. Gas diffusing apparatus comprising a conduit having at least one upwardly extending gas discharge opening, a generally concave deflector positioned above said gas discharge opening, and gas disseminating means positioned within said deflector and extending across at least a part of the open end of said deflector, said gasdisseminating means having a substantial portion of its surface positioned at a level no lower than the bottom edge of said deflector, said gas discharge opening of said conduit being positioned between said deflector and said disseminating means and above the bottom edge of said generally concave deflector.

2. Gas diffusing apparatus comprising a conduit having at least one upwardly extending gas discharge opening, a generally concave deflector positioned above said gas discharge opening, and perforated gas disseminating means extending across the open end of said deflector, said gas discharge opening of said conduit being positioned between said deflector and said disseminating means and above the bottom edge of said generally concave deflector.

3. Gas diffusin apparatus comprising a conduit having at least one upwardly extending gas discharge opening, a generall concave deflector positioned above said gas discharge opening, a second deflecting surface positioned within said generally concave deflector, said second deflecting surface having a substantial portion of its surface positioned at a level no lower than the bottom edge of said generally concave deflector, the edges of said second deflecting surface being spaced away from said generally concave deflector, said gas discharge opening of said conduit being positioned between said generally concave deflector and said second deflecting surface and above the bottom edge of said generally concave deflector.

4. Apparatus as in claim 3 in Whichthe second deflecting surface is generally convex in character.

' SIGURD T. HELSETH. STANLEY T. FAUVER. 

